Characterising Grid Connection Stability of Low Voltage PV Inverters through Real-time Hardware Testing

Abstract

A hardware level study, performed at the Power Networks Demonstration Centre (PNDC), testing seven off-the-shelf PV inverters is introduced in this paper. The objective of this work is to characterise the connection stability limits of the small scale grid-tied PV inverters under a variety of network disturbances represented by step changes in voltage magnitude and phase angle (referred to as Vector Shift - VS) applied on the LV AC terminals of the inverter. Such conditions, often caused by faults in the transmission network, can compromise the connection stability of the PV inverters and potentially exacerbate the network instability if large loss of PV generation ensues. The results presented in this paper reflect a future grid dominated by inverter connected generation with a wide range of inverters behaviours observed under the imposed testing scenarios.